The present invention relates to an active matrix display device, and more particularly to a driving circuit arrangement effective for realization of such a device which is low in cost and small in size and can be fabricated with a high yield.
JP-A-61-145597 has proposed a display device in which the number of connection lines between an active matrix display panel and a driving circuit is reduced in such a manner that a plurality of groups of signal lines (termed source wirings or lines) are connected to signal distributing TFT's (thin film transistors) respectively and one of the signal lines to which a signal is to be inputted is selected by the signal distributing TFT.
JP-A-62-15599 has proposed a display device in which the number of connection lines between an active matrix display panel and an external mounted driving circuit is reduced by incorporating a simple matrix switching circuit into the display panel as a part of a vertical scanning circuit.
In the display device disclosed by the JP-A-61-145597, the turn-on resistance of the signal distributing TFT must be made sufficiently small in order that a signal supplied from the external mounted driving circuit is correctly transferred to each signal line. Therefore, the size of the TFT must be made large. As a result, there are problems that it is difficult to make the turn-off resistance of the TFT sufficiently large and a large change in gate voltage of the TFT upon turn-off thereof is induced by a stray capacitance between the gate and source of the TFT and propagated to the signal line.
The JP-A-62-15599 is silent to the reduction in number of connection lines between such an external mounted horizontal driving circuit and a liquid crystal panel.